C++ 关键字： long
来自 cppreference.com
[编辑] 用法
[编辑] 示例
运行此代码
#include <climits> #include <concepts> #include <iostream> #include <limits> #include <locale> static_assert( sizeof(long) >= 32 / CHAR_BIT && sizeof(unsigned long) >= 32 / CHAR_BIT && std::numeric_limits<long>::min() <= -2'147'483'647l - 1 && //' std::numeric_limits<long>::max() >= 2'147'483'647l && //' std::numeric_limits<unsigned long>::max() >= 4'294'967'295ul); //' // 'long long' and 'unsigned long long' are available since C++11 static_assert( sizeof(long long) >= 64 / CHAR_BIT && sizeof(unsigned long long) >= 64 / CHAR_BIT && std::numeric_limits<long long>::min() <= -9'223'372'036'854'775'807ll - 1 && std::numeric_limits<long long>::max() >= 9'223'372'036'854'775'807ll && std::numeric_limits<unsigned long long>::max() >= 18'446'744'073'709'551'615ull); // concepts are available since C++20 static_assert( std::integral<long> && std::integral<long long> && std::integral<unsigned long> && std::integral<unsigned long long> && std::floating_point<long double>); // Note that 'long' cannot modify 'float' static_assert( std::same_as<decltype(0l), signed long int> && std::same_as<decltype(0ll), signed long long int> && std::same_as<decltype(0ul), unsigned long int> && std::same_as<decltype(0ull), unsigned long long int> && std::same_as<decltype(0.l), long double>); template <typename T, typename... Ts> concept all_same = (... and std::same_as <T, Ts>); static_assert( all_same<long, long int, signed long, signed long int> && all_same<unsigned long, unsigned long int> && all_same<long long, long long int, signed long long, signed long long int> && all_same<unsigned long long, unsigned long long int>); #define OUT(...) std::cout << #__VA_ARGS__ << " = " << __VA_ARGS__ << '\n' int main() { std::cout.imbue(std::locale("en_US.UTF-8")); OUT(sizeof(long)); OUT(std::numeric_limits<long>::min()); OUT(std::numeric_limits<long>::max()); OUT(std::numeric_limits<unsigned long>::max()); OUT(sizeof(long long)); OUT(std::numeric_limits<long long>::min()); OUT(std::numeric_limits<long long>::max()); OUT(std::numeric_limits<unsigned long long>::max()); } #undef OUT
可能的输出
sizeof(long) = 8 std::numeric_limits<long>::min() = -9,223,372,036,854,775,808 std::numeric_limits<long>::max() = 9,223,372,036,854,775,807 std::numeric_limits<unsigned long>::max() = 18,446,744,073,709,551,615 sizeof(long long) = 8 std::numeric_limits<long long>::min() = -9,223,372,036,854,775,808 std::numeric_limits<long long>::max() = 9,223,372,036,854,775,807 std::numeric_limits<unsigned long long>::max() = 18,446,744,073,709,551,615
